Electromagnetically operated device



April 10, 1945. J. o. KNowLEs Erm. 2,373,479

ELECTRO-MAGNETICALLY OPERATED DEVICE Filed May ll, 1942 Patented Apr. 10, 1945 UNITED STATES PATENT OFFICE nLEe'raoMAGNErio Davie ALLY orERA'rED `ohn Okell Knowles, Colwyn Bay, and Meredith Noel Humphreys, Llandudno, North Wales, and John Stanley Davies, Chester, England, as= signers to Broolihirst Switchgear Limited, Chester, England, a British company Application May 11, 1942, serial No. '442,568 In Great Britain June 26, 1941 7 Claims.

` present invention is to render such gear compara* tively nois'eless whilst the coil is energized. A further object of the invention is to increase the working life of devices of the above kind.

In the usual construction of gearing operated by an A. C. electro-magnet, the armature of the magnet is xed to the part which it has to operate by means which do not permit of relative movement between the armature and the said part; the pull of the magnet on the armature has to resist an opposing force which is sometimes considerable, for example that due to stressed spring contacts, so that when, upon energization of the magnet on making the working stroke, the armature is pulled over into contact with the. poles of the magnet or other arresting stop, the opposing force tends to pull it away; where the current is D. C. and of sui'licient magnitude the opposing force is steadily resisted, but when the current is alternating and therefore of uctuating magnitude noisy vibration is produced which, although it may be countered by a phase splitting device inserted in the pole faces, is more pronounced when the armatLu-e does not bed itself accurately against the poles of the magnet.

According to the presentl invention there is provided yin or for use in an electro-magnetically operated device, an armature which is supported so that it is substantially rigid in a direction normal to the pole faces but is free to move in other directions so that the pole faces oi the armature and electro-magnet can accommodate themselves snugly one against the other.

According to a further feature of the invention there is provided in or for use in an electro-mag netically operated device, an armature characterized by a rubber or like resilient insert (e. g., a bush) interposed between the armature and the part of the device whereon said armature is carried, to permit accommodation of the pole faces of the armature to the pole faces of the electromagnet.

The invention also provides in or for use in an electro-magnetically operated device comprising an electro-magnet and a movable armature, an armature having a connecting means comprising a pin and a resilient rubber or like bush for said pin located in a hole in the armature so that the armature is flexibly carried by the pin, the pin being adapted for connection to a part of the mechanism to be operated by the electro-mag netic device. Conveniently the pin is attached to an arm mounted on the operating shaft of, for

, example, a contacter or other electro-magneti cally operated device.

The expression rubber where used in this specification is intended to mean natural and artificial rubber and rubber-like compositions and materials which, in themselves, have a high or fairly high degree of resiliency.

- The invention will be further described, by way of example, with reference to the accompanying drawing which shows embodiments of the invention as applied to an electro-magnetically operated contactor. On the Vdrawing- Figure 1 is a cross-sectional View of one embod iment, the cross-section being taken on the line I--I of Figure 2,

Figure 2 is an elevation.

The device shown in Figures l and 2 comprises an electro-magnet I0 having a laminated core. I I and pole pieces I2, and an armature I3 adapted, when the magnet IU is energized, to engage the pole pieces I2, The armature I3 comprises the usual laminations which are clamped and riveted or bolted at lil between cheek plates I5. A hole located mid-way between the ends of the armature extends transversely through the cheek plates I5 and the laminations, the diameter of the hole at Il, where it passes through the centei-most laminations, being greater than its diameter atV I6, where it passes through the outermost laminations and the cheek plates l5, so that a housing is provided for a rubber bush I8. The bore of the bush is of less diameter than that of lthe hole Athrough the laminations and the cheek plates so that a hollow pin or sleeve i9, whichis a tight fit in the bush and passes right through and beyond the lamina-tions and through holes 20 in the cheek plates, flexibly supports the armature so that it can rock slightly from side to side on the sleeve relatively to the axis thereof. The compression oi the bush I8, however, is such that the armature I3 is not movable normally in a direction at right angles to the axis of the pin It. This sleeve serves as a means for attaching the armature to a U-section arm 2l mounted on the operating shaft 22 of the contacter or other mechanism, the sleeve being tted on a due to the alternating magnetic field, and causel an objectionable amount of noise. Because of the compression of the bush I8 in its housing there is an almost absolute solid resistance to any movement of the armature in a direction normal to the pole faces, indicated by the arrow N. On

the other hand, the large overhang of the pin I9v on either side of the bush I8 enables the armature to tilt sufficiently to obtain the required snug fitting of the pole faces.

We claim:

l. An electro-magnetically operated device comprising an electro-magnet, an armature in operative relation to said electro-magnet and having a hole to receive an armature-supporting pin, means to be actuated by the electro-magnet, an armature-supporting pin in said hole, means connecting said pin to the said actuated means, a rubber bush on said pin interposed between the pin and the armature, means confining said bush circumferentially and aty its ends so that it is maintained under such considerable compressive stress as to prevent deformation by any forces acting in a direction normal to the pole face of the armature, whereby the armature is rigidly supported by the pin in a direction normal to its pole face while being permitted limited axial tilting movement on said pin.

2. An electro-magnetically operated device, comprising an electro-magnet, an armature in operative relation to said electro-magnet and having a hole to receive an armature-supporting pin, said hole being of larger diameter than the pin and being further enlarged in diameter intermediate its ends to form a bush housing, means to be actuated by the electro-magnet, an armature-supporting pin in said hole, means connecting said pin to the said actuated means, and a rubber bush on said pin and located in said housing land co-niined Vthereby circumferentially and at its ends so that it is maintained under considerable compressive stress and against deformation by any forces acting in a direction normal to the pole face of the armature, whereby the armature is rigidly supported by the pin in a direction normal to its pole face while being permitted limited aXial tilting movement relative to said pin.

3. An armature for an electro-magnetic device, having a hole to receive means whereby it can be attached to an actuated member of the device, a rubber bush confined in said hole circumferentially and at its ends under such compressive stress as to prevent deformation of the bush under forces acting in a direction normal to the pole face of the armature, and a pin fitting tight in said bush but of less diameter than the hole in the armature.

4. An armature for an electro-magnetically operated device, having a hole to receive means whereby it can be attached to an actuated member of said device, the hole being enlarged in diameter intermediate its ends to form a bush housing, a rubber bush in said housing and conned circumferentiall'y and at its ends thereby under considerable compressive stress, and a pin fitting tight in said bush but of less diameter than the hole in the armature.

5. An electro-magnetically operated device, comprising an electro-magnet, an armature in operative relation to said electro-magnet and having a'hole to receive an armature-supporting pin, said hole being of larger diameter than the pin and being further enlarged in diameter intermediate its ends to form a bush housing, means to be actuated-by the electro-magnet, an armature-supporting pin in said hole, means connecting said pin to the said actuated means, and a Vrubber bush on said pin and located in said housing :and conned thereby circumferentially and at its ends so that it is maintained under such considerable compressive stress and thereby held against deformation by any forces acting in a direction normal to the pole face of the armature, whereby the larmature is rigidly supported by the pin in a direction normal to its pole face while being permitted limited axial tilting movement on said pin, the pin havin-g a considerable overhang on either side of the bush to facilitate such non-linear movement.

6. An armature for anV electro-magnetically operated device, having a hole to receive means whereby it can be attached to an actuated member of said device, the hole being enlarged in diameter intermediate its ends to form a bush housing, a rubber bush in said housing and coniined circumferentially and at its ends under considerable compressive stress, and a pin fitting tight in said bush but of less diameter than the hole in the armature, the pin having considerable overhang on either side of the bush to facilitate limited non-linear movement only of the armature relatively to the pin.

7. An 'electro-magnetically operated device, comprising an electro-magnet, an armature in operative relation to said electro-magnet and comprising a plurality of laminations superimposed and means securing said laminations together, the laminations having registered holes and the holes inv the laminations forming the middle portion of the armature being of larger diameter than the holes in the laminations forming the side portions of the armature so as to form a bush housing, means to be actuated by the electro-magnet, an armature-supporting pin in the hole in the armature formed by the holes in the laminations, means connecting said pin to said actuated means, a rubber bush on said pin and located in said housing yand confined thereby circumferentially and at its ends so that it is maintained under considerable compressive stress and against deformation by any forces acting in a direction normal to the pole face of the armature, whereby the armature is rigidly 

